Nanbaka: 10x the stupidity
by CatPockyLady
Summary: Nanba Prison. Home to many dangerous criminals and is impossible to escape from. However, is it impossible for Cell 13 and a new Inmate?
1. chapter 1

**Chapter 1: Why me?!**

 **This crossover has been in my head ever since I watched Nanbaka so... making a Ben 10 crossover with it... don't judge me.**

 **This takes place at the end season 4 of Ben 10 Omniverse. Credits go to Futaba Shō and Man of Action**

It was a day like no other in Bellwood.

The birds were chirping, the sun was shining and to top it off, there was an explosion at Plumbers HQ...

Wait a minute.

In the smoke, three individuals ran in coughing to see what was happened and the damages. The first individual was a grey haired man wearing a red Hawaiian shirt, white pants and black shoes, named Max Tennyson, the second individual was a tall blue-furred feline-like alien wearing a black skin suit with blue armor plates, named Rook Blonko, the third individual was wearing a green striped and white hoodie with the number '10' down the middle, with shaggy brown hair and emerald eyes was none other than the universal hero, Ben Tennyson.

"What in the world happened here?"coughed Grandpa Max, "I do not know Magister Tennyson perhaps a break-in?". Opening the lab doors, only to see two small grey amphibious creatures known as Galvans arguing. "Blukic, I told you that using a quantum wench was a bad idea!" Shouted Driba, a galvan technician "I told you that Driba!" shouted Blukic, another galvan technician.

"No you didn't"

"yes I did"

"no you didn't"

"Yes I did"

" **Enough!** " Interrupted Ben. "what _exactly_ happened in here, you know _before_ the alarms went off." At that both Blukic and Driba grinned to their ears(?) "well, if you must know we have upgraded the teleportation pad." Said Driba showing off the telepad, though it looks as if nothing changed. "Ok," Ben looked around the machine "what's so different about it?" At that question the two galvans gasped in bewilderment. " _ **what's**_ different about it?' Why, we've have finally made our own personal dimensional teleport pad!" Explained Driba.

"However the circuitry was almost fried by a certain galvan" Blukic then looked away and whistled absent-mindlessly. "Thankfully there was hardly any damage done to it." At that, everyone looked at each other skeptically, seeing as how little damage caused a uproar of plumbers thinking something exploded "yeah, I don't think setting off the alarm should be called 'hardly any damage done" muttered the shaggy-haired teen hero.

"Well after traveling to another dimension using the 23rd Mr. Smoothies, we thought it'd be easier to travel if we had our own." Answered Driba. "So how long will it take for you to finish it?" Inquired Max. "Right about..." Blukic and Driba then replaced the fried wire with a new one and then closed the lid of the teleport pad "now" replied both galvans.

"Now, all we need is a test subject..." stated Driba at that statement everyone glanced at Ben. "Um, can there be another candidate?" Ben asked nervously.


	2. Hey! A shooting star! I think

**Chapter 2**

 **This takes place in the first Season of Nanbaka. Interluding the aftermath of the 3rd episode. Also there's a reference in this chapter! Try to guess what it is.**

 **P.S. I'm so sorry this took so long, school and life have been getting on me...**

 _I cannot reveal its exact location. That information is classified at the nation's highest level of secrecy._

 _Nanba Prison..._

 _The impregnable prison on a remote island floating on the sea. The lastest technology and guards recruited from around the world, give it Japan's largest and the world's highest-level, security network._

 _Even the famous Alcatraz Island is full of Joelle's and opportunities to escape when compared to this place._

 _The full truth of this place will never be revealed to the world..._

 _That is because this is Nanba Prison._

 _No one has ever escaped successfully from this prison._

 _"Damn it, No. 15!_ I swear when I find you... First with the moronic ninja, and now this?" an angry bald man, with crimson red eyes, a scar on his right eye and a black suit with a red tie. Looking enraged beyond belief.

As if _that_ were true...

What people of Nanba don't know is that there's an inmate that can break out of every cell, lock, puzzle. You name it, in record time.

Currently, This inmate was outside, looking at the sky, brightly lit by the prison lights and stars. This was Jyugo. A teen with black hair, tinted red on the sides of his face, wearing a classic slightly worn prison outfit. His most noticeable feature was his eyes, both of them were different colors and kept changing in different angles.

Jyugo suddenly sneezed. "I can't help for feel if someone is talking about me..." He absentmindedly said, wiping his nose with his finger. Sighing, he looked down at the sea, reflecting the black starlit sky. _'What happened earlier tonight was a bit... How should I say, anticlimactic... Not to mention Hajime'_ he then shivered at bit at the thought.

Other than what had transpired, nothing at all interesting had happened.

It was _boring_ , to say the least.

Not that the teen was complaining. Looking up at the sky again, more specifically, the stars. He'd heard from Uno that if you wish on one hard enough, your dream would come true. He scoffed at the thought, he had never been one to believe in wishes, or them coming true.

However...

Quickly looking behind him, then to the left, and to the right, then finally back up to the sky. He'd be lying if he hadn't been thinking about making one. No one would know about it.

Well besides Uno...and Rock, and Nico... And pretty much anyone who's been around him for five seconds...

 _'I'm too much of an open book...'_ Jyugo thought dejectedly. Suddenly a green flash of light went across the sky. "Oh, a shooting star." He said in his usual monotone voice. _'Might as well try this 'wish' thing.'_ He thought, shrugging.

He then closed his eyes and thought very hard about his wish as the star went by.

' _~Riiiiiiiiiiiiii~'_

Jyugo's eyes shot open at a faint sound, it sounded like... screaming? He looked around, trying to locate where the sound was coming from. Instead he saw Hajime a yard away. Coming straight for him. _'Oh shit.'_ Jyugo gulped, the sound got a bit louder, it was clear enough to decern it. It was _definitely_ screaming.

"No. 15...when I get my hands on you... You're _dead meat._ " the bald man growled, stalking towards the multi-eyed boy. He had sent Seitarou and Yamato to different parts of the prison in hopes of covering more ground but knowing them, Yamato would get lost and Seitarou would have to go find him...

Hajime went to the outside part of the prison to look for the multicolor eyed inmate, but now that he's found him, his mood has improved exponentially. There _was_ one thing was annoying him, though. _'~Riiiiiiii~' he_ couldn't tell _where_ that sound was coming from and was honestly getting on his last _good_ nerve but it only amplified when he went outside.

Roughly grabbing the teen by the collar, he started to drag him back to his cell. "Ack-hey! Hajime! Put me down!" The inmate started to thrash around trying to get out of the supervisor's grip but to no avail. "Shut it brat! You have cause enough problems for one night!-"

 ** _"Boom!"_**

Whatever Hajime was going to say, died out by sudden movement. Both inmate and supervisor looked up and saw a green fireball, headed straight for the middle of the prison. "Oh it's the shooting star!" Jyugo said, surprised to find a star in such close range. "What... the hell..?" Hajime was at a lost for words.

"Hey Hajime, do you hear... screaming?" Questioned Jyugo. Both looked at each other, then at the 'star' and listened more closely.

 ** _"RiiiiiiiiiAAAAAAAAAAAAAAHHHHHHHHHHHHHH"_**

The 'star' crashed in the middle of the prison, making a huge smoldering crater. The alarms were blaring from the unknown craft crashing down. In the smoke and ashes of the crater, a figure rose up from it.

It was unlike anything anyone had seen. A humanoid creature, made of molten rock and fire, rose from the site. It had comically big hands and a strange green hourglass symbol in the middle of its chest. The creature opened its (what would it be it's) mouth and said...

"Is there a welcoming committee here?"

 **Finally! I did the next chapter! I swear I'm not dead, thank you, watchers and readers. I hope to do the next chapter a little faster so thank you for reading and until next time!**


	3. The New Comer is an Alien!

**Hello my readers! I am so sorry I'm so inconsistent with this! Hopefully this chapter will make it up to you! Ben 10 belongs to Man of Action**

 **Nanbaka belongs to Futaba Shō**

 **And without further ado,**

 **Enjoy!**

 _" **Boom!"**_

 _Whatever Hajime was going to say, died out by sudden movement. Both inmate and supervisor looked up and saw a green fireball, headed straight for the middle of the prison. "Oh it's the shooting star!" Jyugo said, surprised to find a star in such close range. "What... the hell..?" Hajime was at a lost for words._

 _"Hey Hajime, do you hear... screaming?" Questioned Jyugo. Both looked at each other, then at the 'star' and listened more closely._

 ** _"RiiiiiiiiiAAAAAAAAAAAAAAHHHHHHHHHHHHHH"_**

 _The 'star' crashed in the middle of the prison, making a huge smoldering crater. The alarms were blaring from the unknown craft crashing down. In the smoke and ashes of the crater, a figure rose up from it._

 _It was unlike anything anyone had seen. A humanoid creature, made of molten rock and fire, rose from the site. It had comically big hands and a strange green hourglass symbol in the middle of its chest. The creature opened its (what would it be it's) mouth and said..._

 _"Is there a welcoming committee here?" It rasped._

 **N _ow that you saw what happened at Nanba Prison, let's go back to what happened before then shall we~?_**

 ** _~in Bellwood at Plumbers HQ~_**

"Why couldn't you guys use someone else?" Groaned Ben, standing in front of the transporter nervously. "Relax Ben, besides even if you land in somewhere inhabitable I'm sure you can survive!" Stated Driba.

 _"Gee, how reassuring Driba...'_ Ben thought sarcastically, "I think it should you be fine Ben, you've been through worst." Rook said, trying to ease his friend uneasiness. Ben sighed in resignation and looked the machine in front of him. While he has been in worst situation it doesn't take out the anxiety of the unknown. It irritates him. "Hey, how much longer, anyway?" Demanded Ben, tapping his foot impatiently. Blukic emerged from the console and gave a annoyed glare "you can't rush science." He said simply and went back down to the console while Ben mocked mouthed him from behind.

Ten minutes later of waiting and hearing nothing but the taps of the console, Blukic and Driba re-emerged with satisfied expressions. "Well?" Grandpa Max asked, "is it done?" Ben looked over to see what they had to say in anticipation. "Yes, it's done" both Galvans finally said.

" _FINALLY!"_ Ben exclaimed, earning looks from Grandpa Max and Rook "what? You know I'm impatient." He defended, looking away slightly embarrassed.

Grandpa Max sighed at his grandson's immaturity while Driba and Blukic got out some goggles. "Since this is a test and we don't know how it'll go, we'll need these." Holding one up to Rook, who got two and walked over, extending one to Grandpa Max.

"Hey, I don't get one?" Ben asked, but it went unheard as Rook and Grandpa Max went behind the console with goggles on.

"I doubt you'll need one since you're the test subject." Rook stated matter-of-factly, earning him a sharp glare from his partner.

"Where is Ben going to be sent to?" Questioned Max.

"Hopefully, to one we've been to..." Ben muttered under his breath.

"It's Ben 23's dimension, just a little on the outskirts of the city."

Blukic answered. "In any case, we're ready to go!"

Driba said giving Ben a thumbs up and starting up the machine.

The teleporter came on with whirring sound and automatically lifted up into Ben's direction, meanwhile an uneasy feeling welled up in Ben's throat, while he has used this thing before it was in dire circumstances and they have tested it but it didn't take out the lump in his throat. Apparently the feeling was mutual with his grandpa and Rook, both not know where Ben could end up or if he could come back.

The machine finally charged up enough when several blaring red screens that said **_'malfunction'_** came up on the screen in front of the Galvans.

"What's happening?!" Max ordered as the two Galvans hopped around the keyboard. "That's what we're trying to find out!" Replied Driba frantically trying to stop the machine, meanwhile Rook attempted to shut down the machine using the lever but no matter how hard he pushed down it wouldn't budge.

"Magister Tennyson, the lever is stuck!" Rook

"Try and shut it off manually!" Ordered Max, typing away at the console with the two Galvans.

Ben looked back and forth as he saw everyone in a panic. He was about to go help but the machine shot it's beam at him before he or Rook could react!

 _"BEN!"_ Both Rook and Max shouted as Ben was teleported to his new destination.

The first thing Ben felt was fuzzy needly feeling. It came in jolts of fuzz throughout his body, like it was asleep and it needed to wake up.

Ben opened his eyes only to see darkness and maybe some dust particles, either from the beam or something Ben honestly didn't care much. _'So this is what it's like...'_ Ben acknowledged, while it was never the first time he teleported he never savored it. It was always when something was going on like an evil warlord or something, never for the hell of it.

Ben's thoughts were immediately interrupted by suddenly being forced into a direction of bright light. He shut his eyes tight so he wasn't blinded.

Then he felt the fuzzy feeling vanish from his body like a spell.

He slowly opened his eyes and scanned the area.

He was in the air.

And he was falling.

"Oh, _Shhhhhiiii-!"_ He yelled as gravity suddenly took control. Squinting his eyes as he plummented down, he clenched his teeth and started to scan through the Omnitrix. _'Cmon, something with wings...!'_ He thought as he swiped from green icons filled with many aliens.

"Aw, _GREAT!_ Just when the universe couldn't make my life _**anymore**_ difficult!" Ben panicked, to no one in particular.

Letting out a frustrated yell, Ben slammed down on the watch closing his eyes for whatever alien he got.

Ben's body immediately started heating up to abnormal temperatures. His body burned, then burst into flames. Instead of killing him instantly, it instead wrapped around him. His skin was replace with hard molten rock as the fire spread around him, his hands turned comically large and contained magma.

Ben had turned into a Pryonite, named _'Heatblast'._

Opening his hollow yet magma filled eyes, Heatblast then covered himself in a ball of fire.

He failed to notice the island in front of him. He then failed to notice that the island was occupied.

He also failed to notice...

 _The island was a **Prison.**_

 **Ok! I made another chapter!**

 **I apologize for the wait, again I hope this chapter makes it up! Also, since I have to test next week I won't be able to make another chapter.**

 **But I'll be back!**


	4. Prison Run Pt1

**Hey, readers! Thank you so much for the support for this fanfic! It really means a lot to me. Also, since school has started I'll get this and possibly the next chapter done in parts, how many parts is how long each chapter is.**

 **Also I'm really sorry for how long this took, I will try to do better. Thank you for your patience**

 **Anywho, on to the story!**

 _ **Last we left off, Ben landed in the middle of Nanba Prison as Heatblast. Now we see how he's going to adapt to the new environment.**_

* * *

 _'Crap, crap, crap, crap!'_ Was all Ben could think of as he avoided a tranquilizer bullet, all while running from a bunch of guards. Normally, this would be a piece of cake, being made of fire and all, but due to the fact that these guys look like normal humans and didn't have fire retardant suits. Ben would rather avoid burning people alive.

"Ok this is stupid," Heatblast rasped stopping in his tracks. Outstretching his hands and focusing his energy, his hands shot out torrents of fire and he moved them into a circle. Raising his hands up the charred earth under him shifted and rose from the ground, making a meteor-like hovercraft. "I need to find out _where_ and _what_ this place is."

With that idea set in mind, Heatblast flew out of the sand den and above the area to get a clear view of his surroundings. "Dude..." He rasped, mesmerized by the colorful buildings with bright lights covering them. _'If I didnt know any better, I'd think this place was some sort of hidden city...'_ Ben thought.

His thoughts were then interrupted by bright watchlights being shined on him. Covering his eyes with his arms, Ben heard a feminine yet authoritative voice on the intercom then spoke out. _"This is the warden! You are trespassing in an unauthorized area, state your purpose or be removed with extreme prejudice!" _She spoke.

 _'I need to get out of here. Now.'_ Not even paying any attention to the intercom's warning, Ben flew away from the lights and into the prison.

 _However,_ he didn't get very far. The universe seems to have a _hilarious_ sense of humor as the guards managed to get a fire-hose and shot a torrent of water onto Heatblast just as he was flying away.

Causing him to be put out and fall off the flaming rock.

 _"Aw, MAN!"_ Heatblast yelled trying to turn his flame on, but it kept flicking on and off due to the wind and the wetness.

 _'The floor is starting to get awfully close!'_ He thought, as he tried turning his flames on one more time.

Fire spread around him, emitting a light for any inmates still up. Turning to the right, Ben had hope to turn to an open space.

He _miscalculated_.

He did indeed find an open space but being about 4 feet from the ground caused Heatblast to spiral up in the air and fall straight towards a wall.

With no time to dodge, Ben braces for impact. He didn't hear a familiar ticking from his chest.

"That creature crashed near building five!" A guard shouted. "Follow the smoke there and alert all building five guards!" He ordered.

* * *

'Lovely, just _lovely_...' Hajime inwardly griped. Not only did he have some punk kid trying to work his way out of his iron grip, but _NOW_ something crashed landed here and is causing a panic throughout the prison.

Events just _love_ to make more work for him, apparently. If he was to find out what's here he'll have to first deal with his current problem. "Hajime! Lemme go!" Jyugo whined, trying to get out of the Supervisor's grip to no avail.

"Shut it, No. 15!" He growled. He needed to find his cell and find whatever landed here, but from what he heard it landed near the Monkey's domain. Jyugo struggled against the bald man's grip but it was pointless to do so, he then felt himself be lifted and thrown into his cell again, his cell mates already up from the noise.

Stalking off from the now locked cell, Hajime needed to get to Building 5 to see what happened. _'The sooner we find it, the better. Got enough on my plate as is.'_ The man irritatingly thought. "Seitarou!" Hajime yelled and a small, spikey blue haired man came running, but tripped and fell gracelessly.

Hajime sighed and shook his head. "Seitarou, there's an unknown intruder in the prison and was last seen in Building 5. You're in charge while I check it out." Seitarou got up and sputtered "B-but Supervisor, wh-what if something happens while you're gone?" He asked, fearful of dealing with unruly inmates. "You and Yamato should be capable enough to deal with any problems should they come up," the man said, then immediately grimaced. "As soon as you find him..." Hajime finished with a sweat drop, he needed to find that creature. _Fast._

* * *

Ben was brushing off any rubble from himself and was currently hiding behind a pillar nearby where he crashed.

He'd of course leave, but there were guards on every corner. Looking down at the Omnitrix, he thought about his options of what alien could be most useful.

 _'Brainstorm could work... meh, the planning would take to long and he isn't very fast...'_ he thought, ducking when a light came near. _'Jetray could get me out quickly! No, too conspicuous...'_ he shook his head at his ideas, then had a lapse of inspiration, a form he hadn't changed into for a while... _'ChamAlien! That could work!'_ Looking around for a secluded spot, Ben spotted a door a few pillars down, most likely a storage closet. "Bingo." He whispered with a smirk.

Observing the area once again, Ben quietly moved pillar to pillar, not noticing the camera watching his every move.

* * *

"Hehe, this kid is interesting..." commented a man in a dark room, surrounded with the blue glow of computer screen with a smirk. He had dark skin adorned with a red tattoo that was reminiscent of fire, only seen partially by his lax and unkempt uniform. "Very interesting indeed." he continued as he watched Ben make it to the storage room.

* * *

Ben reaches out to the handle, and slowly turns it to not make any noise. _'So far, so good..'_ the teen thought, until he heard footsteps not to far from where he was. _'The universe LOVES to make things difficult for me, doesn't it?'_ Ben deadpanned and his movement stilled.

"Man, what a mess..." the guard groaned, adjusting his hat as he walked closer. Ben quickly tried to open the door, but found it was stuck in place, causing the brunet to inwardly curse. Looking back to see how much time he had before was caught, Ben got a look at the guard.

While Ben couldnt see much in the darkness, he definitely saw that the guard getting to close for his liking, which made the brunet involuntarily sweat. Ben immediately shook his head and focused on the door. It shouldn't take much force to open, just a shove of his shoulder.

 _Thump!_

Another shove.

 _Thump!_

And with a third, final shove, the door opened and Ben scrambled inside and closed the door just in time.

The guard stopped right at the storage room door, and slowly looked around.

Ben silently prayed the guard wouldn't notice him as he watched through a small hole in the door. He noticed the guard's features, he had dark brown hair with mint streaks in them. _'Is that even allowed in a prison?'_ The teen thought, his breath then got caught in his throat as the guard glanced to the direction of the door.

Red eyes looked as if it was burning right through Ben despite it not being directed at him.

Time had seemed to stop, until the guard shrugged and walked off, once he was far enough away, Ben to let out a breath of relief.

"Ok, task one complete." He said to himself as he tapped the screen of his watch, revealing a black... with a green hourglass illuminating a holographic image of different creatures. Ben scrolled through one hologram after another in search of the correct alien. Once he found a holographic image of a reptilian-like alien, he grinned.

"Alright..." Ben rose his hand up in the air, then slammed it down on the green hourglass.

 _"It's Hero Time!"_

* * *

 **Ok! Nothing too exciting now, but more will come~**

 **Also thank you for your patience with me, and I hope to see you soon!**

 **Bye bye~**


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